Storybook is a free (open source) novel-writing tool for creative writers, novelists and authors which will help you to keep an overview of multiple plot-lines while writing books, novels or other written works.
Storybook assists you in structuring your book
Store all information about your characters and locations in one place. Then, use the included Storybook features for managing chapters, scenes, characters and locations. A simple interface is provided to enable you to assign your defined characters and locations to each scene and to keep an overview of your work with user-friendly chart tools.